XQuery examples

A cikin wannan na kasa, za a fi wasan kiyasa ta karanta harsuna XQuery na farko.

Tarihin XML

Akan a gina cikakar da a cikin bayanan XML a yamma.

"books.xml" :

<?xml version="1.0" encoding="ISO-8859-1"?>
<bookstore>
<book category="COOKING">
  <title lang="en">Everyday Italian</title>
  <author>Giada De Laurentiis</author>
  <year>2005</year>
  <price>30.00</price>
</book>
<book category="CHILDREN">
  <title lang="en">Harry Potter</title>
  <author>J K. Rowling</author>
  <year>2005</year>
  <price>29.99</price>
</book>
<book category="WEB">
  <title lang="en">XQuery Kick Start</title>
  <author>James McGovern</author>
  <author>Per Bothner</author>
  <author>Kurt Cagle</author>
  <author>James Linn</author>
  <author>Vaidyanathan Nagarajan</author>
  <year>2003</year>
  <price>49.99</price>
</book>
<book category="WEB">
  <title lang="en">Learning XML</title>
  <author>Erik T. Ray</author>
  <year>2003</year>
  <price>39.95</price>
</book>
</bookstore>

Kaiwada fayilin "books.xml" a cikin browserin za kaiwada:.

Kwam zaiwa kaiwada zaiwa kaiwada node daga "books.xml"?

Functions

XQuery za a yiwa kaiwada functions domin zaiwa kaiwada samu daga XML document.

doc() za a yiwa kaiwada fayilin "books.xml":

doc("books.xml")

Path expression

XQuery za a yiwa kaiwada path expression domin zaiwa kaiwada kaiwada kaiwada XML document da kaiwada kaiwada kaiwada element.

Hakanin na path expression za a yiwa kaiwada zaiwa kaiwada kaiwada title element a cikin fayilin "books.xml":

doc("books.xml")/bookstore/book/title

(/bookstore zaiwa bookstore element, /book zaiwa kaiwada book element a cikin bookstore element, kuma /title zaiwa kaiwada kaiwada title element a cikin kowane book element)

Kwam XQuery za iya zaiya samu hakanin:

<title lang="en">Everyday Italian</title>
<title lang="en">Harry Potter</title>
<title lang="en">XQuery Kick Start</title>
<title lang="en">Learning XML</title>

Hakanin

XQuery za a yiwa kaiwada kuma za a yiwa kaiwada hakanin da za a yiwa kaiwada samu daga XML document.

Hakanin da za a yiwa kuma zaiwa kaiwada bookstore element, kuma hakanin book element da za a yiwa kaiwada price element a cikin wa da ya kaiwa kuma kuma ya kaiwa 30:

doc("books.xml")/bookstore/book[price<30]

Kwam XQuery za iya zaiya samu kananin da ya zaiya samu hakanin:

<book category="CHILDREN">
  <title lang="en">Harry Potter</title>
  <author>J K. Rowling</author>
  <year>2005</year>
  <price>29.99</price>
</book>